Rubidium time standard exciter.
This is a small bulb that, in the original device, was positioned next the cell shown in the previous sample. It is, I am told, filled with a larger amount of rubidium than the larger cell, and serves as the the exciter, transmitting radio waves of the correct frequency to excite the lower-pressure rubidium vapor in the larger cell. (Lower pressure means narrower spectral line, and thus higher accuracy.)Source:eBay seller nhbbobb1985Contributor:Theodore GrayAcquired:19 November, 2008Text Updated:10 January, 2009Price: $38Size: 0.75"Purity: 99.9%